diff --git a/src/exif.cpp b/src/exif.cpp
index 51f02e82..dcd81f7a 100644
--- a/src/exif.cpp
+++ b/src/exif.cpp
@@ -828,7 +828,7 @@ namespace Exiv2 {
         append(blob, mio2.mmap(), mio2.size());
 #ifdef DEBUG
         if (wm == wmIntrusive) {
-            std::cerr << "SIZE OF EXIF DATA IS " << std::dec << io.size() << " BYTES\n";
+            std::cerr << "SIZE OF EXIF DATA IS " << std::dec << mio2.size() << " BYTES\n";
         }
         else {
             std::cerr << "SIZE DOESN'T MATTER, NON-INTRUSIVE WRITING USED\n";
diff --git a/src/tiffimage.cpp b/src/tiffimage.cpp
index f2d1cc07..35fe41c1 100644
--- a/src/tiffimage.cpp
+++ b/src/tiffimage.cpp
@@ -2171,7 +2171,7 @@ namespace Exiv2 {
             return true;
         }
 #ifdef DEBUG
-        std::cerr << "Not an image tag: " << key << " (4)\n";
+        std::cerr << "Not an image tag: " << tag << " (4)\n";
 #endif
         return false;
     }
diff --git a/xmpsdk/include/XMP_Environment.h b/xmpsdk/include/XMP_Environment.h
index a6b6c6cb..e8554570 100644
--- a/xmpsdk/include/XMP_Environment.h
+++ b/xmpsdk/include/XMP_Environment.h
@@ -96,7 +96,10 @@
 
 #if defined ( DEBUG )
     #if defined ( NDEBUG )
-        #error "XMP environment error - both DEBUG and NDEBUG are defined"
+		#undef NDEBUG
+		#warning
+		#warning "XMP environment - DEBUG and NDEBUG defined.  NDEBUG has been undefined"
+		#warning
     #endif
     #define XMP_DebugBuild 1
 #endif